1. Field of the Invention
The present invention relates to a click structure of a rotary electric part used in a vehicular air conditioner for example.
2. Description of the Prior Art
A conventional rotary electric part will now be described with reference to FIGS. 32 and 33. A case 21, which is formed by molding a synthetic resin, comprises a square base portion 21b having a ring-like recess 21a and a cylindrical support portion 21d having a central through hole 21c. Plural contact pieces 22 are embedded in the base portion 21b of the case 21.
A shaft member 23, which is also formed by molding a synthetic resin, comprises a shaft portion 23b having a central through hole 23a and a ring-like rotary member 23c provided at a lower end of the shaft portion 23b. The shaft portion 23b and the rotary member 23c are formed integrally by molding and the shaft portion 23b is formed in the shape of a straight cylinder almost equal in diameter throughout the whole thereof.
A conductive pattern 24 as a code pattern is formed on the underside of the rotary member 23c. In the shaft member 23 provided with the conductive pattern 24, the support portion 21d is inserted through the through hole 23a and the rotary member 23c is received into the recess 21a, whereby the shaft member 23 is secured to the case 21 rotatably.
A mounting plate 25, which is a metallic plate, comprises a flat plate portion 25b having a hole 25a, a pair of leg portions 25c bent at a right angle from the flat plate portion 25b, and plural mounting portions 25d also bent at a right angle from the flat plate portion 25b. The shaft portion 23b and the support portion 21d are inserted from their front end portions into the hole 25a, allowing one side of the rotary member 23c to be covered with the flat plate portion 25b, and lower ends of the leg portions 25c are bent toward the underside of the case 21 to mount the case 21 and the shaft member 23 with each other. Thus, the mounting plate 25 functions as both a mounting means and a housing.
In the rotary electric part thus constructed, when the shaft portion 23b of the shaft member 23 is rotated, both rotary member 23c and conductive pattern 24 rotate and the contact pieces 22 come into sliding contact with the conductive pattern 24, producing a pulse signal.
In such a rotary electric part, a knob (not shown) can be attached to a front part of the shaft portion 23b. In this case, since there are knobs of various shapes and constructions, it is necessary to provide a variety of knobs 23b for conformity with such various shapes and constructions. Also as to the conductive pattern 24 it has so far been necessary to provide a variety of conductive patterns.
In the conventional shaft member 23, since the shaft portion 23b and the rotary member 23c having the conductive patterns 24 are formed integrally with each other, it is necessary to provide a different mold each time one of the shaft portion 23b and the conductive pattern 24 is different. This results in not only an increase of cost but also the necessity of providing various shaft members 23.
In the conventional mounting plate 25, at every change in diameter of the shaft portion 23b to which a knob is to be attached, it is necessary to provide a mounting plate 25 of a different hole 25a, thus requiring the provision of various mounting plates 25, which leads to an increase of cost.
Such a rotary electric part is mounted to a printed circuit board (not shown) and, as shown in FIG. 32, a push-button switch 26 is disposed on the printed circuit board which is positioned within the through hole 21c, to operate the electric part.
Since the support portion 21d of the case 21 and the shaft 23b of the shaft member 23 are cylindrical, the rotary electric part is superior in space factor, permitting another electric part to be disposed in the central space.
In the shaft member 23 of the conventional rotary electric part, since the shaft portion 23b and the rotary member 23c having the conductive pattern 24 are integrally formed by molding, it is required to provide a different mold each time either the shaft portion 23b or the conductive pattern 24 is different, thus giving rise to the problem that not only the cost increases but also various shaft members 23 must be provided.
In the conventional mounting plate 25, moreover, a mounting plate 25 of a different hole 25a must be provided at every change in diameter of the shaft portion 23b to which a knob is to be attached, thus giving rise to the problem that various mounting plates 25 are needed and the cost increases.
Accordingly, it is an object of the present invention to provide a rotary electric part which permits standardization of components and which is inexpensive.
According to the first embodiment adopted by the invention for solving the above-mentioned problems there is provided a rotary electric part comprising a case having a wall portion and a cylindrical support portion, the cylindrical support portion extending upright from the wall portion and having a through hole at its center, a cylindrical, rotatable shaft member fitted on the support portion of the case, a rotary member which is mounted on the shaft member and which can be rotated with rotation of the shaft member, contact pieces provided on either the case side or the rotary member side, and a conductive pattern provided on either the case side or the rotary member side, wherein the shaft member and the rotary member are formed as separate members, the shaft member is provided with a first snap leg portion, and the rotary member is mounted to the shaft member by the first snap leg portion.
According to the second embodiment for solution adopted by the invention there is provided, in combination with the first means, a rotary electric part further including a housing covering at least one side of the rotary member, and wherein the shaft member is inserted into a through hole formed centrally of the housing.
According to the third embodiment adopted by the invention there is provided, in combination with the first means, a rotary electric part wherein the shaft member has a stepped portion and the rotary member is engaged with the stepped portion and is held grippingly by both the stepped portion and the first snap leg portion.
According to the fourth embodiment adopted by the invention there is provided, in combination with the first embodiment, a rotary electric part wherein the first snap leg portion extends axially and is opposed in proximity to an outer peripheral surface of the support portion of the case.
According to the fifth embodiment adopted by the invention there is provided, in combination with the first means, a rotary electric part wherein an outer periphery of the shaft member is formed with a radially extending shoulder portion, and the first snap leg portion extends to one side in the axial direction with the shoulder portion as a boundary.
According to the six embodiment there is provided, in combination with the first means, a rotary electric part wherein the first snap leg portion is provided three or more.
According to the seventh embodiment adopted by the invention there is provided, in combination with the fifth means, a rotary electric part wherein the shaft member is provided with a second snap leg portion, the second snap leg portion extending to the opposite side in the axial direction with the shoulder portion as a boundary.
According to the eighth embodiment adopted by the invention there is provided, in combination with the fifth means, a rotary electric part wherein the rotary member and the housing are fitted on the shaft portion of the shaft member on the side where the first snap leg portion is provided.
According to the ninth embodiment adopted by the invention there is provided, in combination with the first means, a rotary electric part wherein the rotary member comprises a rotor having a concave-convex portion which constitutes a click mechanism and an insulating substrate disposed on the rotor and provided with the foregoing conductive pattern or contact pieces, and the first snap leg portion is engaged with the insulating substrate.
According to the tenth embodiment adopted by the invention there is provided, in combination with the ninth means, a rotary electric part wherein the concave-convex portion is provided on an outer circumferential portion of the rotor and is positioned inside the contour of the insulating substrate.